The present invention relates to a solar tracking concentrating collector capable of achieving moderately high concentration ratios. Due to its specific, unique design elements, the present invention shows a number of advantages over prior art concentrators.
Most practical prior art concentrators have been curved reflective surface designs like the solar tracking parabolic reflective mirror types, or the primarily stationary curved reflective troughs. Since large curved mirror surfaces must have detailed structural support, or be constructed of materials of sufficient thickness to support their shape, materials expense for the structural requirements of these large area curved reflectors are bound to be relatively high. This is especially true if these reflectors must be exposed to wind loading. Since collectors of the present design utilize flat reflective surfaces which can be supported by gas or linear tension, they are capable of being constructed of materials of considerably thinner guage. These less-expensive materials should provide considerable economic advantage in the construction of solar concentrators where large reflective areas are required. Additionally, since all materials required in the present design are of either a flat sheet or linear nature, many commonly available inexpensive materials should be applicable.
Only solar tracking concentrators have proved able to maintain consistently high concentration ratios throughout yearly solar motions. Since prior art tracking concentrators have been curved reflectors necessitating pivoting of their rigid shapes around an axis, they have required physical spacing between their reflectors to prevent physical interference and shadowing of each other during tracking orientations. However, concentrators of the present design, because of their unique flexible-shape method of tracking orientation, maintain complementary shape and adjacency throughout their range of tracking orientation, thus requiring no intermediate spacing and utilizing collection area more efficiently.
As a consequence of this continuous contiguity of reflector surfaces, concentrators of the present design can easily be housed inside a protective structure with covering glazing . . . an embodiment that provides a number of advantages relative to prior art concentrators. As compared with parabolic reflectors, one of these advantages will be found in the increased life expectancy of receiving tube and reflector surfaces protected by the covering glazing from the abrasive external environment. Protection from external factors may also be afforded to the tracking mechanism by the collector housing and should reduce maintenance and increase useful life. Additionally, it can be expected that a considerable reduction in heat loss from the solar absorbing element will result from having it inside a sealed enclosure.